Vehicle loader

ABSTRACT

A refuse loader adapted for use with a refuse collection vehicle and including a packer plate movement mechanism of an improved, simplified construction. The mechanism includes a packer plate which is pivotally mounted on a reciprocable carrier so as to be able to move while extended with the carrier to a position for engaging a load of refuse, then be swung through an arc to collect and compact the refuse and thereafter be moved with the carrier to discharge portion of the loader. The same cycle may thereafter be repeated as desired. The improved design provides, by means of an improved link, cylinder, packer plate, and carrier arrangement, a mechanism having improved flexibility in relation to known mechanisms previously used in counterparts of the loading mechanism of the invention, and also having improved reliability and simplicity. The function previously achieved with four hydraulic cylinders is now accomplished using only two. In addition, the unit has inherent safety features not heretofore available in such units. In addition to providing a novel mechanism and operating cycle, the unit affords a compact design which enables an associated refuse collection vehicle body to be shortened, for increasing the effective load able to be handled by the truck and improving the maneuverability thereof.

United States Patent 1 May 16, 1972 Boda 154] VEHICLE LOADER [72]Inventor: Robert A. Boda, Oshkosh, Wis.

[73] Assignee: Leach Company, Oshkosh, Wis.

[22] Filed: June 5, 1970 [2]] Appl. No.: 43,935

[52] US. Cl ..2l4/83.3, 100/233 511 Int. Cl. ..B65f3/00 [58] Field ofSearch 214/833, 503; 100/233 [56] References Cited UNlTED STATES PATENTS2,888,158 5/1959 Wood ....214/83.3 X 2,798,624 7/1957 Brown et al....214/83.3 3,143,230 8/1964 Gollnick 214/833 X 3,297,180 1/1967 Park eta1 ..214/83.3

Primary Examiner-Albert J. Makay Attorney-Greist, Lockwood, Greenawaltand Dewey [5 7] ABSTRACT A refuse loader adapted for use with a refusecollection vehido and including a packer plate movement mechanism of animproved, simplified construction. The mechanism includes a packer platewhich is pivotally mounted on a reciprocable carrier so as to be able tomove while extended with the carrier to a position for engaging a loadof refuse, then be swung through an arc to collect and compact therefuse and thereafter be moved with the carrier to discharge portion ofthe loader. The same cycle may thereafier be repeated as desired. Theimproved design provides, by means of an improved link, cylinder, packerplate, and carrier arrangement, a mechanism having improved flexibilityin relation to known mechanisms previously used in counterparts of theloading mechanism of the invention, and also having improved reliabilityand simplicity. The function previously achieved with four hydrauliccylinders is now accomplished using only two. In addition, the unit hasinherent safety features not heretofore available in such units. Inaddition to providing a novel mechanism and operating cycle, the unitaffords a compact design which enables an associated refuse collectionvehicle body to be shortened, for increasing the effective load able tobe handled by the truck and improving the maneuverability thereof.

1 1 Claims, 8 Drawing Figures Patented May 16, 1972 3,662,908

4 Sheets-Sheet 1 IN VEN TOR Easem- A. BODA Patented May 16, 1972 4Sheets-Sheet 2 INVENTOR Power /4- BYMJm/MO, Wf

ATT'YS .4

Patented May 16, 1972 4 Sheets-Sheet B INVENTOR 2055/2 r 4. 5 004Munro-q ATT'YS BY I /f Patented May 16, 1972 4 Sheets-Sheet 1 P m WAM wW n Q 8 0 RM VEHICLE LOADER BACKGROUND OF THE INVENTION The presentinvention relates to refuse collecting vehicles, and in particular, toan improved construction of refuse loaders for use with truck bodies ofthe type in which refuse is loaded into a bin or refuse receivingportion of the loader, then picked up by a powered packer plate, andmoved into a discharge area from which it is transferred to the interiorof the body proper so that the truck body may be fully loaded withmaterial of maximum density before emptying thereof.

Refuse collecting vehicles of the type in question are known to bedesigned to meet certain structural and functional criteria; one suchdesirable feature is that a loader for refuse includes power equipmentthereon to the maximum practical degree, to minimize labor cost and timespent in refuse collection. This is important from the standpoint ofdirect operational cost as well as because business and residentialowners commonly prefer that refuse be picked up only duringv certainhours of the day.

Inasmuch as the regions in which refuse is dumped for burning, or forremoval to a more remote area are often somewhat distant from the placesat which refuse is collected, it is desirable to insure that the maximumvolume of refuse can be packed in a truck body, and it is also desirablethat the material be packed as densely as possible so that the maximumpossible weight thereof can be accommodated between trips to theunloading area.

It is also a requirement for a satisfactory refuse or garbage collectingvehicle that the design provide for maximum access to a loading orpickup area thereof. Therefore, refuse collecting trucks commonlyinclude a wide open bin extending across the entire rear of the body sothat the bin is easily accessible from either side and from the rear.Such a construction, when associated with its operating mechanism,inherently makes the vehicle undesirably heavy in the rear, therebylimiting the amount of useful load that may be placed therein,particularly where regulations limit the maximum vehicle loading peraxle as well as gross vehicle weight. In other words, vehicles havingheavy mechanisms in an overhanging position produce a sub stantialmoment about the rear axle, undesirably concentrating excess weight onthe axle, although not necessarily producing an excessive gross weight.

In addition, extending the mechanism behind the rear wheels in this waytends also to increase the overall length of the vehicle and to limitthe manuever ability thereof, which is a significant drawback invehicles intended for use in cramped areas such as alleys, docks and thelike.

Accordingly, in view of the various characteristics desired in refusecollecting and loading equipment, and in view of the shortcomings ofvarious prior art loader constructions, it is an object of the presentinvention to provide an improved refuse loader assembly.

Another object of the present invention is to provide a refuse loaderhaving a simplified construction of the essential elements.

Another object is to provide a refuse loader having a mechanism suchthat movement of a single actuator served to position the packer plateand move the carrier in a desired sequence.

Another object of the present invention is the provision of a loadermechanism wherein a single movement sequence accomplishes these objects,and wherein no outside control is needed to perform the transition fromone step or function to the succeeding function or step exceptcontinuous movement of the pistons within associated hydrauliccylinders.

Another object is the provision of such a system making extensive use ofexisting components in the interest of simplicity and economy.

A further object is to provide a refuse loader in which a reduced numberof components is required to perform an operation previously requiring agreater number of parts or elements.

A further object is the provision of a loader unit which may be mountedfor pivotal movement in respect to an associated trunk body.

A still further object of the invention is to provide a mechanism for arefuse loader in which a packer plate and an associated carrier aremoved as a unit to the pickup area of the loader, and in which the plateis then moved to pick up and compact the refuse, and thereafter movedwith the carrier as a unit into a second position for discharging therefuse from the loader into an associated vehicle.

Still another object of the invention is to provide a mechanism formoving a packer plate from a first position for engaging refuse to asecond position for discharging the refuse and which includes a carrierfor pivotally supporting a packer plate, and one or more operating linksattached at one end thereof to the plate and at the other end to anactuator operated by a hydraulic cylinder and wherein the end associatedwith the actuator is positioned for relative movement within the carrierto a limited extent so that movement of the actuator will move the platerelative to the carrier and then move the carrier and the plate togetheras a unit.

Another object is to provide a construction wherein the packer plate andthe packer plate carrier are both moved by a common actuator, and inwhich the plate and the carrier move in a desired sequence.

A further object of the present invention is to embody an improvedconstruction within a compact loader unit.

The present invention achieves these objects and other inherent objectsand advantages by providing a mechanism including a packer plate movablebetween first and second positions for picking up refuse and dischargingit, a carrier unit positioning the packer plate for pivotal movement, apair of operating links each having one end attached to the plate andthe other end received in a slot in the carrier, and a pair of hydrauliccylinders for moving the other ends of the links to extend the packerplate, move the plate and carrier as a unit to first position then movethe plate to a retracted position and move the carrier and plate as aunit to the second position for discharging refuse picked up by movementfrom the first position.

The manner in which these are accomplished will become more clearlyapparent when reference is made to the detailed description of thepreferred embodiments of the invention and to the accompanying drawings,forming a part hereof, in which like reference numerals indicatecorresponding parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary sideelevational view, showing the loader of the invention in a normalposition of use associated with a truck body;

FIG. 2 is an enlarged view, partly in section and partly in elevation,of the loader unit of the invention;

FIG. 3 is a fragmentary end elevational view of a portion of the loaderof FIG. 2, taken along lines 3-3 thereof;

FIG. 4 is a perspective view of the loader unit of the invention;

FIG. 5 is a partially schematic vertical sectional view of the loader ofthe invention, showing the packer plate, carrier, and operating links inone position thereof;

FIG. 6 shows the elements of FIG. 5 in another position thereof;

FIG. 7 shows the elements of the FIGS. 5 and 6 in still another positionthereof; and

FIG. 8 shows the elements of FIGS. 5-7 in still another operationalposition thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Beforereferring in detail to the embodiments of the invention illustrated inthe drawings, it will be understood that the invention is useful in anumber of different environments and may be embodied in various forms,and that it may be used on various types of associated vehicles,including those with or without auxiliary load packing means, andincluding trucks having bodies mounted for dumping, or other formsofunloading the contents thereof. It will also be understood that aprincipal use of a loading device of this type is for loading refuse,but that other materials may be loaded into associated truck bodies withloaders embodying the principles of the invention.

Referring now to the drawings in greater detail, the invention will beillustrated by reference to an embodiment wherein the loader of theinvention is associated with the body portion 22 carried by a truck 24,and wherein means in the form of a hinge 26 and a hydraulic piston andcylinder assembly 28 serve to attach the loader 20 to the rear endportion 30 of the truck body 22.

Referring now to FIG. 2, it will be seen that the loader 20 is comprisedof a number of principal elements, including a hydraulic cylinder andpiston assembly 32 for moving a carrier assembly 34 with a reciprocatingmotion generally parallel to a top edge portion 36 of a combinationloader body frame element and carrier guide 38. The cylinder and pistonassembly also serves to move the packer plate 40 by movement of theoperating links 42 extending between a link mounting flange portion 44of the plate 40 and a carrier drive and link positioning assembly 46.FIG. 2 also shows that the loader 20 includes a pair of side wallportions 48, 50, and a generally arcuate bottom wall 52 forming, incombination with a vertical end wall 54, a refuse receiving area 56lying below the sill 58, which in turn defines the lower edge of therefuse receiving opening 60 which is presented when the plate 40 is inanother position of use, as will be described in further detail herein.

FIG. 2 also shows a top guide stop 62 associated with an upper endportion of the carrier guide 38, and mounting means 64 including a shaft66 for maintaining the mounting ears 68, 70 associated with the carrier34 and the plate 40 respectively, in position for permitting pivotalmovement of the packer plate 40.

Referring now also to FIGS. 3 and 4, it is shown that the hydraulicpiston and cylinder assembly 32 includes a doubleacting cylinder 72having a mounting ear portion 74 thereof mounted by means of a fastener76 to a lower portion 78 of the lower frame member 80. A movable endportion 82 of the assembly 32 is attached to the piston rod 84 andmounted by a fastener 86 to a transverse rod 88. Attached to theopposite end of the rod 88 is a similar end portion (not shown) of aleft hand piston and cylinder assembly (also not shown), whichcorresponds to the right hand assembly 32 and is similarly constructedand arranged. FIG. 4 also shows that the operating link 42, in additionto being joined at its lower end 90 (FIG. 2) to the flange 92, is alsojoined at its other end 94 to the rod 88, thereby forming, with thefastener 86 and movable end portion 82 of the piston rod 84, a carrierdrive and link positioning assembly 96. In the form of the inventionshown, the carrier 34 includes a pair of oppositely disposed sideportions 98, 100, a forward edge 102, a cover element 104, and a pair ofslots 106, 108 in the sides 98, 100, in which the rod 88 may reciprocatebefore engaging the rounded upper stops 110, 112 or rounded bottom stops114, 116 forming the ends of the slots 106, 108, respectively.

Referring now in particular to the carrier 34, it is shown to bepositioned for movement parallel to the top guide 38 and held in placebetween the top surfaces 118, 120 of the side walls 48, 50 and the lowersurfaces 122, 124 of the top guides 38, 126 by engagement therebetweenof rollers 128, 130, 132, etc., which are associated with the carrier34. Lateral movement of the carrier 34 is limited by the provision ofguide assemblies 134, 136, 138 and 140 which include portions thereofbearing againstthe side walls 142, 144 of the guides 38, 126. Four pairsof adjusting screws 146, 148, and 152 are associated with the guideassemblies 134, 136, 138 and 140 so that resistance to movement of thecarrier assembly 34 with respect to the fixed portions of the loader 20may be adjusted, for reasons which will presently appear.

Accordingly, in view of the above-described disposition of the rollers128, 130, 132 etc., the various surfaces serving as guides, and theguide assembly 134, 136, 138, 140, all of which combine to define thenature and extent and movement of the carrier 34, it will be appreciatedthat movement of the carrier 34 may be accomplished by exertingsufficient forces in either direction on the carrier 34. As shown inFIG. 3, for example, a typical guide assembly l40 preferably includes afixed block 154 to which are attached sleeves 156, 158 for receiving theadjusting screws 152. Acting through springs (not shown) these adjustingscrews may more or less forcefully urge the contact plate 160 againstthe side wall 144 of the guide 38. The block 154 is secured, as bywelding, to a flange 162 on the side 98 of the carrier 34. Therefore,frictional resistance to movement of the carrier 34 may be adjusted byadjusting the sets of screws 146, 148, 150, 152. It will therefore beunderstood that, assuming that there is appreciable resistance todisplacement of the carrier 34, a force acting on the carrier drive andlink positioning assembly 96 will tend to move the rod 88 and itsassociated operating link 42, provided that such movement may beaccommodated by passage of the rod 88, link 42 and associated componentsthrough the opened portions of the slots 106, 108. Reference will now bemade to the operating cycle of the loader, whereby the reasons for thisfact will be made more clear.

Referring now to FIGS. 5-8, inclusive, positions of certain of themovable elements are shown in various portions of a complete operatingcycle. In the position of FIG. 5, the plate 40 is in a fully extendedposition and the carrier 34 is in a position of extreme downwardmovement. In FIG. 6, carrier 34 remains stationery but the plate 40 hasmoved to a retracted position, and in FIG. 7, the carrier 34 and plate40 have moved as a unit to the maximum extent of travel in the oppositedirection. In FIG. 8, the carrier 34 remains in the extreme upwardposition but the plate has been moved to a fully extended position inpreparation for movement of the carrier 34 downwardly to the position ofFIG. 5, from which the cycle will be repeated.

Referring in particular to FIG. 5, it will be assumed that the portionof the loader 20 which receives the refuse has been substantially filedwith refuse so that addition thereto of additional refuse would causethe load to spill out over the sill 58, and that the carrier 34, withthe plate 40 extended has moved to the position shown. This traps refusebetween the arcuate bottom surface 52 of the loader 20 and the frontsurface of the packer plate 40. When an actuating force is applied tothe carrier drive and link positioning assembly 96, provided that therod 88 and its associated parts are movable freely in the slot 106, andthat resistance to arcuate movement of the plate 40 is not sufficientlygreat to prevent rod movement, the link 42 will urge'the flange 92 andthe plate 40 to the position shown in FIG. 6. This serves to compact therefuse and/or move it somewhat upwardly from the receiving area 56 ofthe loader 20. In the position shown in FIG. 6, the rod 88 has reachedits maximum upward movement within the slot 106, and accordingly,continuing upward force supplied thereafter will be applied through theend portion 112 of the slot to the carrier assembly 34, causing it tomove upwardly to the position shown in FIG. 7. Thereupon, refuse carriedby the plate 40 is carried or transferred over the upper edge 164 of thewall 52, from which position it falls or is pushed to the interior ofthe body 22 of the truck 24. FIG. 8 shows that, provided in thisinstance there is resistance to movement of the carrier 34, a downwardforce applied to the rod 88 will first permit the rod 88 to movedownwardly in the slot 106, thereby moving the associated link 42 andplate 40 to the illustrated extended position. This is the normalposition of the carrier 34 and plate 40 when the bin 56 is being loaded.

One feature of the invention which is achieved by the operationalfeatures of the mechanism provided is that in the event, for one reasonor another, there is great resistance to arcuate movement of the plate40 from the extended position (FIG. 5) to the retracted position (FIG.6), and an actuating force continues to be exerted, such force will thentend to move the carrier 34 in the same direction as the force isapplied. In other words, assuming that plate 40 would not undergo apivoting motion, the rod 88 would therefore not be permitted to slideforward, and the carrier 34 and plate 40 would, in effect, be a singleunit, so that the actuating force transmitted through link 42 to theplate 40 would tend to move the entire assembly as a unit. In such acase, if the obstruction to movement of the plate 40 could be bypassedas the carried moved toward an extreme upward position, when theobstruction or obstacle were bypassed, resistance to a retractingmovement of the plate would be diminished and the rod 88 would againmove forward in relation to the carrier 34. As a result, at the end ofthe operating sequence, the carrier 34 and plate 40 would occupy theposition shown in FIG. 7, although the exact movement sequence undergoneby these parts to arrive at this position would be different from theordinarily intended sequence already described. On the other hand, ifthe resistance to arcuate plate movement continued throughout the entirestroke, the position shown in FIG. 7 would never be achieved, but theposition of elements shown in FIG. 8 would result, namely, a position inwhich the carrier 34 would be in its maximum upward position while theplate 40 would remain in the extended position. The possibility ofundergoing these movement sequences is a safety feature, inasmuch as,upon encountering unusual conditions, the mechanism will undergo amovement sequence determined by the portion of the sequence whichpresents the path of least resistance during the portion of the cycle inquestion. Consequently, the cylinder and piston assemblies are not aslikely to be overloaded as they would be in a construction whereinretraction and carrier movement were accomplished by plural pairs ofcylinders rather than merely one pair of cylinders. The presentconstruction also has the advantage of simplicity in that only onecylinder or pair of cylinders need be provided.

Furthermore, the form of linkage is simplified in respect to prior artlinkages. Inasmuch as the mechanism itself is simplified, the controlsystem is simplified, and, in normal use of the mechanism, assuming thatit is properly adjusted, the movement sequence is self operating, andtherefore, separate sequencing controls or elements need not beprovided.

The location and disposition of the elements of the loader of thepresent invention is such that massive elements need not be placed atthe rear portion of the loader. As a consequence, the loader can be madecompact in front-to-rear dimensions and relatively light in weight inrelation to its capacity, thereby allowing a truck to be more compactfor better maneuverability and to have more favorable weightdistribution so that a given gross weight will be more equallydistributed on the truck axles than would be the case in the use ofprior art designs.

Inasmuch as the present construction uses a minimum of links, rods,actuators, and the like, its inherent simplicity provides dependabilityand reliability at low cost.

As can be appreciated by reference to FIGS. 1, 2, and 3, the auxiliaryhydraulic cylinder 28 and its counterpart (not shown) enable the loaderassembly 20 as a whole to be pivoted rearwardly and upwardly about thepoint 26 so that the body 22 of the truck 24 can be emptied in aconventional manner, such as by the use of a body dumping mechanism, arefuse removal plate, or the like.

it will thus be seen that the present invention provides an improvedrefuse loader for use with a collection vehicle having a number ofadvantages and characteristics, including those herein particularlypointed out, and others which are inherent in the invention.

I claim:

1. A mechanism for movement of a packer plate in relation to anassociated refuse loader from a first position for engaging refuse in aload receiving portion of said loader to a second position fordischarging refuse packed and transferred by said plate to the dischargeportion of said loader, said mechanism comprising, in combination, acarrier for a packer plate, a

packer plate pivotally connected to said carrier, at least one operatinglink attached at one end thereof to said plate for causing arcuatemovement thereof between extended and retracted positions upon movementof the other link end relative to said carrier, means connected to saidcarrier for receiving said other link end to permit free but limitedmovement of said other link end, relative to said carrier, and at leastone movable actuator connected to said other link end, whereby movementthereof in one direction will first move said plate to said extendedposition and thereafter move said carrier and said extended plate as aunit to said first position, and movement from said first position inthe opposite direction will first move said plate to said retractedposition and thereafter move said carrier and said retracted plate as aunit to said second position.

2. A mechanism as defined in claim 1 in which said movable actuatorcomprises a double-acting hydraulic cylinder and piston assembly foreach operating link.

3. A mechanism as defined in claim 1 in which said at least oneoperating link comprising a pair of operating links, one of said linksbeing attached to one end of said packer plate and the other link to theother end of said packer plate.

4. A mechanism as defined in claim 1 in which said carrier includes apair of side portions, in which said means for permitting free butlimited movement comprises a slot in each side portion, each sideportion being disposed generally parallel to the direction of movementof said carrier, and in which said carrier includes a cover plateextending transversely of said direction of movement and joining saidtwo side portions to each other.

5. A mechanism as defined in claim 1 in which said carrier includes twoside portions, and in which said mechanism further includes guide meansfor said side portions of said carrier to establish the directions oftravel thereof and to limit the extent of carrier motion in eitherdirection.

6. A refuse loader assembly comprising, in combination, a loader havinga load receiving portion at least partially defined by a generallyarcuate bottom surface and a load discharge portion for dischargingrefuse into the body of an associated vehicle, a reciprocable carrierfor carrying a packer plate, a packer plate for engaging refuse disposedin said load receiving portion of said loader and for transferring saidrefuse to said discharge portion, means attaching said plate to said carrier at a first pivot point to permit said plate to move through an arebetween an extended position for movement toward refuse in saidreceiving portion for engagement thereof, and a retracted position forcompacting refuse and transferring it to said discharge portion, an edgeportion of said plate being thereby adapted to be moved along saidarcuate bottom surface, at least one operating link for moving saidpacker plate, said link having one portion thereof pivotally attached tosaid plate at a second pivot point, and a second portion thereofconnected to a portion of said carrier so as to permit free but limitedmovement of said second portion with respect to said carrier betweenfirst and second stops, and at least one operating piston and cylinderassembly, said assembly having one portion thereof fixed with respect tosaid loader and the other, relatively movable portion thereof connectedto said second portion of said link, whereby limited movement of saidpiston within said cylinder will cause pivotal plate movement andwhereby further piston movement will cause movement of said carrier.

7. A loader assembly as defined in claim 6 wherein said loader assemblyincludes means thereon for hingedly mounting said loader to a portion ofan associated truck body, and also includes means for maintaining saidloader in closely associated relation to said body as well as for movingsaid loader away from said body for unloading said truck body.

8. A loader assembly as defined in claim 6 in which said loader assemblyhas a portion thereof adapted to be hingedly connected to an associatedtruck body, and which further includes a pair of hydraulic cylinders forholding said loader adjacent said truck body for loading said body andfor pivotally moving said loader away frorn said body for emptying saidbody.

9. A loader assembly as defined in claim 6 in which said at least oneoperating link comprising a pair of oppositely disposed operating links,one for each end of said packer plate.

10. A loader assembly as defined in claim 6 in which said at least onepiston and cylinder assembly comprises a pair of piston and cylinderassemblies, and in which said at least one link comprises a pair oflinks, with one of said assemblies being associated with each of saidsecond portions of said links.

11. A loader assembly as defined in claim 6 in which said loader furtherincludes a rear wall portion joined to and extending upwardly from therear margin of said arcuate bottom surface, a pair of side wallportions, a front wall portion having the top surface thereof definingthe bottom of said discharge portion, in which said side walls arejoined together by a top wall assembly extending transversely to anupper portion of said side walls, and in which said carrier includes aloader cover wall portion adapted, in combination with said top wallassembly and said packer plate, to cover substantially the entire rearportion of said loader in one position of said carrier and said plate.

* l IIK

1. A mechanism for movement of a packer plate in relation to anassociated refuse loader from a first position for engaging refuse in aload receiving portion of said loader to a second position fordischarging refuse packed and transferred by said plate to the dischargeportion of said loader, said mechanism comprising, in combination, acarrier for a packer plate, a packer plate pivotally connected to saidcarrier, at least one operating link attached at one end thereof to saidplate for causing arcuate movement thereof between extended andretracted positions upon movement of the other link end relative to saidcarrier, means connected to said carrier for receiving said other linkend to permit free but limited movement of said other link end, relativeto said carrier, and at least one movable actuator connected to saidother link end, whereby movement thereof in one direction will firstmove said plate to said extended position and thereafter move saidcarrier and said extended plate as a unit to said first position, andmovement from said first position in the opposite direction will firstmove said plate to said retracted position and thereafter move saidcarrier and said retracted plate as a unit to said second position.
 2. Amechanism as defined in claim 1 in which said movable actuator comprisesa double-acting hydraulic cylinder and piston assembly for eachoperating link.
 3. A mechanism as defined in claim 1 in which said atleast one operating link comprising a pair of operating links, one ofsaid links being attached to one end of said packer plate and the otherlink to the other end of said packer plate.
 4. A mechanism as defined inclaim 1 in which said carrier includes a pair of side portions, in whichsaid means for permitting free but limited movement comprises a slot ineach side portion, each side portion being disposed generally parallelto the direction of movement of said carrier, and in which Said carrierincludes a cover plate extending transversely of said direction ofmovement and joining said two side portions to each other.
 5. Amechanism as defined in claim 1 in which said carrier includes two sideportions, and in which said mechanism further includes guide means forsaid side portions of said carrier to establish the directions of travelthereof and to limit the extent of carrier motion in either direction.6. A refuse loader assembly comprising, in combination, a loader havinga load receiving portion at least partially defined by a generallyarcuate bottom surface and a load discharge portion for dischargingrefuse into the body of an associated vehicle, a reciprocable carrierfor carrying a packer plate, a packer plate for engaging refuse disposedin said load receiving portion of said loader and for transferring saidrefuse to said discharge portion, means attaching said plate to saidcarrier at a first pivot point to permit said plate to move through anarc between an extended position for movement toward refuse in saidreceiving portion for engagement thereof, and a retracted position forcompacting refuse and transferring it to said discharge portion, an edgeportion of said plate being thereby adapted to be moved along saidarcuate bottom surface, at least one operating link for moving saidpacker plate, said link having one portion thereof pivotally attached tosaid plate at a second pivot point, and a second portion thereofconnected to a portion of said carrier so as to permit free but limitedmovement of said second portion with respect to said carrier betweenfirst and second stops, and at least one operating piston and cylinderassembly, said assembly having one portion thereof fixed with respect tosaid loader and the other, relatively movable portion thereof connectedto said second portion of said link, whereby limited movement of saidpiston within said cylinder will cause pivotal plate movement andwhereby further piston movement will cause movement of said carrier. 7.A loader assembly as defined in claim 6 wherein said loader assemblyincludes means thereon for hingedly mounting said loader to a portion ofan associated truck body, and also includes means for maintaining saidloader in closely associated relation to said body as well as for movingsaid loader away from said body for unloading said truck body.
 8. Aloader assembly as defined in claim 6 in which said loader assembly hasa portion thereof adapted to be hingedly connected to an associatedtruck body, and which further includes a pair of hydraulic cylinders forholding said loader adjacent said truck body for loading said body andfor pivotally moving said loader away from said body for emptying saidbody.
 9. A loader assembly as defined in claim 6 in which said at leastone operating link comprising a pair of oppositely disposed operatinglinks, one for each end of said packer plate.
 10. A loader assembly asdefined in claim 6 in which said at least one piston and cylinderassembly comprises a pair of piston and cylinder assemblies, and inwhich said at least one link comprises a pair of links, with one of saidassemblies being associated with each of said second portions of saidlinks.
 11. A loader assembly as defined in claim 6 in which said loaderfurther includes a rear wall portion joined to and extending upwardlyfrom the rear margin of said arcuate bottom surface, a pair of side wallportions, a front wall portion having the top surface thereof definingthe bottom of said discharge portion, in which said side walls arejoined together by a top wall assembly extending transversely to anupper portion of said side walls, and in which said carrier includes aloader cover wall portion adapted, in combination with said top wallassembly and said packer plate, to cover substantially the entire rearportion of said loader in one position of said carrier and said plate.